Power transmission



My 30, 1940. NYE AL 7 2,209,608

POWER TRAKSMISSION Filed Feb. 23, 1958 INVENTORS HUGH C. NYE fir! NERRHJ. A. HAYDEN 'ATTORNEY reamed July so, 1940 PATENT OFFICE POWER TRANSMISSION Hugh 0. Nye and Merrill k Hayden, Detroit,

Mich, assignors to Vickers Incorporated,

troit, Mich, a corporation of Michigan Application February 23, 1938, Serial No. 192,030 7 50laims.

This invention relates to power transmissions and more particularly to those of the fluid type "wherein a power transmitting fluid, such as oil. and hereinafter referred to as such, is utilized for the transmission of power between one or more pumps and one or more fluid motors.

The invention is particularly concerned with a power transmission system adapted for operating a plurality of hydraulic motors in prede- 10 termined sequence and may be used, for example, for a hydraulically operated breaching machine.

In the art of broaching machines it is common to provide a maintool operating slide for pulling a breaching tool through a hole in a piece of work and to provide an auxiliary slide-for han-1 dling the breaching tool at its opposite end while the tool is disconnected from the main slide for the purpose of inserting. a new work piece in position. Broaching machines of this character are also frequently provided with a work shifting and clamping slide reciprocable transversely'of the tool to position a new work piece for broaching as well as to hold the work piece while the breaching operation is performed. I I

It is an object of the present invention to provide a hydraulic power transmission system particularly adapted for the automaticoperation of a breaching machine of this character and which, when started, will operate automatically 3 to cause the slides to move in proper sequence through repeated cycles continuously until WDped at will. I

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred form of the present invention is clearly shown.

Inthe drawing: 1 Y g The single figure is a diagrammatic view show- 'ing a hydraulic circuit a preferred form of the present invention.

A tank It ,contains a supply 0! oil which may be withdrawn through suction conduits l2 and M, by a pair of pumps l6 and I), adapted for operation by acommon prime mover, not shown. Pump It has a delivery conduit 20 in which is inserted a suitable relief valve 22 for discharging .oil to the tank through a by-pass conduit 24 whenever a predetermined pressure is ekceeded in conduit 2|;

' Conduit 20 leads to the pressure pcrtof a spring centered, open center, four-way valve 26. Valve 25 has its tank ports connected to the ta'iik by a conduit 23. Conduits 34 and 32 lead from' the cylr I6- mderportstotherodandheadsidearespectively.

. far enough to engage the tool holding means 38,

of a fixed piston-34 on which is reciprocably mounted a movable cylinder 35. The latter forms the main slide of the breaching machine and may be provided with suitable tool attaching means 38, adapted to automaticallygrasp the end 5 of a tool when the latter is inserted therein and to automatically release the same when the cyl- -inder 35 isdown;

The pump It has a discharge conduit 40 in which isinserted a relief valve 42 for by-passing oil to the tank through-a conduit 44 whenever a predetermined pressure is exceeded in conduit- 40.. Inserted in the conduit 40 is a pressure reducing valve 45 for the purpose of preventing the pressure ina conduit 48, from rising above a predetermined value. The valve 46 may com-, prise a movable member 43 which controls the flow from-a chamber 45 to a chamber 41. The member 43 is balanced with respect to the pres-. sure in chamber 45 but is exposed to pressure in '2 chamber 41 pushing upwardly against a spring 49 and against the oil in a. chamber 5| which is maintained therein by seepage past the piston portion of member 43. A pilot relief valve 53 may be adjusted to determine the maximum pres- 2 sure in chamber 5| and thus the pressure in chamber 41 at which the valve will start to close.

At any pressure below this value the valve remains open.

A check valve ill is open-to free flow of 'oil from 30 the conduit to a conduit 52 I which leads to the pressure'port of a springbiased solenoid operated iour-way-valve 54. A conduit 56 connects the tank ports of valve 54 to the tank It. The cylinder ports of the valve are connected by conduits 58 and with the rod and headsides, respectively, of a stationary piston 52. A cylinder 64 is reciprocably mounted on the piston-62 and forms a tool handling slide having a tool receiving socket 85. v

A breaching tool is indicated at 68, adapted to be lifted by the cylinder 54 to be inserted through a hole Ill in a work piece 12 when it is positioned against an. abutment I4. The tool 58, when lifted is automatically locked thereto and may be pulled through the hole It by the cylinder. in the well known manner. As the lower end of the tool 68 leaves the hole III, the work piece 12 may be per- 50 mitted to drop away from the abutment 14, a stationary deflector I3 being provided to deflect the work piece to one side, and the breaching tool may bereturned to engage the socket G6 which then lowers the tool downwardly to the position shown here. A new work piece then. positioned beneath the abuhnent 14.

For the purpose of feeding new work pieces into position and for clamping them during breaching, a work handling slide is formed by a cylinder 18. The latter is provided with a work piece holder maybe 15 in the form of an angle block having a cen- 82 to the cylinder ports .of a spring biased, solenoid operated, four-way valve 84. The pressure port of valve 84 commlmicates by a conduit 88 with a check valve 88. A conduit 88 extends from the conduit 48 to the check valve 88 which is open to free flow from the conduit 88 to the 'oonduit I he tank ports of valve 84 are. connected to Mk by a conduit 8|. It will be understood that the cylinder 18 is normally positioned to reciprocate transversely in a plane at right angles to plane 0! tb drawing, the arrangement shown. being used in darity of illustration.

For the purpose of, at times, utilizing the output of both pumps I8 and II, !or operating the main cylinder 38, a solenoid mated'spring biased, two-way valve 82 is provided, having its pressure port connected .to. the conduit 48 by the branch conduit 84. The controlled port of valve 82 connects by a conduit 88 with the pressm'e conduit 28. Suitable drain connection to the valve 82 is established by a conduit 88. Valve 82 may be shifted to the right to open the valve by an operating solenoid I88 and. is normally spring biased to closed position.

For the purpose of controlling the four-way valves in proper sequence, a control circuit is provided as follows: From one side of a suitable electric power line LI, a normally open push button starting switch I84 connects bya conductor I88 .to the operating coil of a holdingrelay I88 and the other side 01 the line L2. The holding circuit II8 of the relay connects toa normally closed-push button stopping switch 2 to the line LI. The relay I88 controls a circuit extending from LI through a normally open limit switch II4, which is adapted to be closed by a cam II5 on the cylinder when the latter is in its downward position. From the limit switch I I4, a conductor II8 extends to the controlled contacts of the relay I88, from which a conductor II8 extends to the operating coil of a holding relay I28 and line L2. The holding circuit of the relay I28 extends by a. conductor I22 through 8. normally closed limit switch I24 tothe line LI; The switch I24 is adapted to be actuated bya cam I28, carried by the cylinder 38 and positioned to open the switch I24, a short distance before.

del' it whenever the latter reaches the leftward limit of itsstroke. The limit switch I38 controls a circuit including a conductor I88 which extends to the operating coil of a holding relay I38.

aeoaooe holding circuit of the latter extends by a con ductor I48 through a normally closed two-circuit limit switch I42 and to the line LI. The limit switch I42 is operated by a cam I43 whenever cylinder 88 is in its lower position. The relay I 88 controls a circuit extending from the line LI by a conductor I44 through the operating solenoid ofthe valve 84 to line L2. The limit switch I38 also controls a circuit extending by a conductor I48 to a normally open limit switch I48, operated by a cam I58 on the cylinder whenever the lat ter reaches the upper limit of itsmovement. .A conductor I52 extends from the switch I48 to the operating coil of holding relay I54. The holding circuit of the latter extends by a conductor I55 to line LI through a double throw limit switch I58 adapted to be actuated by a cam I58 carried by the cylinder 38 when the latter reaches the upper limit of its movement. The relay I54 controls a circuit extending from LI by a conductor I88 and branch conductors I82 and I84 to the solenoid I88 and to a solenoid I88 connected by a lever I88 to the operating stem I18 of the 'valve 28. The limit switch I58 and a normally open limit switch I12 operated by a cam I13 when cylinder 18 is in its right hand position, are in a series circuit extending from LI by conductors I14 and I18 to the operating coil 01' a holding relay I18 and line L2. The holding circuit of the latter relay extends 'by a conductor I88 to the other contacts of limit switch I42, previously described, and to line LI. The relay I18 controls a circuit extending from LI by a conductor I82 to the solenoid I88 connected of thelever I88.

In operation, starting with the parts in position, shown in the drawing, and the pumps I8 and I8 operating, fluid delivered by the pump I8 is bypassed from the pressure port to the tank ports of the open center valve 28, thus unloading the pump I8, as shown by the solid line arrows. Delivery irom the pump I8 is blocked by the stalling to the opposite end of cylinders 84 and 18, at the bottom and right hand limits, respectively, of their travel and accordingly pressure builds up. as shown by the dotted arrows, sufilciently to open the relief valve 42 by-passing oil to the tank through conduit 44, as shown by the solid line arrows.

To starigthe machine the starting switch I84 is closed manually which energizes the relay I88 through conductor I88. This closes the circuit extending from LI through switch II4, conductor II8, relay I88, conductor H8 and coil 01' relay I28'to line L2. The relay I28 closesia circuit extending from line LI through conductor I28 and the solenoid of valve 84- to line L2. The valve 84 is accordingly shifted to the right to-connect the pressure port with conduit 88 and the tank ports with conduit 82. moves to the left to position a fresh work piece beneath the abutment 14. The oil is delivered for this movement from pump I8, through conduit 48, valve 48, conduit 88, check valve 88, conduit 88, valve 84 and conduit 88 to the head end oi cylinder 18. Oil from the rod end passes through conduit 82, valve 84 andconduits M and 28 to the The cylinder 18, accordingly) tank. The relays I88 and I28 are, of course, held closed by their respective holding circuits aiter they are once energized momentarily.

As the cylinder 18 reaches the left end of its travel,- cam. I34 closes limit switch I38, which energIzes the coil of relay I38 through conductor I38; The relay I38 establishes a circuit through a conductor I44 to the solenoid of valve 54, shifting-the latterto the right to connect the pressurelport with conduit to and the tank ports with conduit 58. The cylinder 64, accordingly, moves upwardly, oil being delivered from the pump I8 through the conduit 40, valve, conduit 48,- check valve 50, conduit 52, valve 54 and conduit 60=to the head end of cylinder 64. Fluid returning from the rod end passes through conduit 58, valve 54 and conduit 56 to the tank. It will be noted that the oil delivered to the cylinder 64 as well as that delivered to cylinder 16 passes through reducing valve 46. The valve is adjusted so that the normal pressure required for moving these cylinders does not cause the valve to close. When, however, the valve 82 is moved to connect conduits 94 and 86, valve 46 prevents the much higher pressure, which is built up in conduits 20 and 40 for operating cylinder 36, from being transmitted to the head ends of cylinders 64 and 16. These latter cylinders may thus be of lighter construction than would otherwise be necessary.

As the cylinder 64 reaches the upper limit or its travel, limit switch I48 is closed, establishing the circuit from LI through the limit switch I30 (now closed), conductor I46, switch I48, conductor I52 and the coil of relay I54 to line L2. Closing of the relay I54 establishes a circuit through conductors I60, I62 and I64 to the solenoids I- and I66. The valve 02 is accordingly shifted to the right to connect conduits 84 and 88 thus permitting the delivery of pump I8 to flow through conduit 40, and conduits 84 and 38 to join the delivery of pump I6 in the conduit 20.

The energization of solenoid I66 lifts the stem I ofvalve 26 to connect the conduit with the conduit 32, permitting oil delivered by both pumps to flow from conduit 20 to the conduit 32, to the head end of cylinder 36. Oil returning from the rod end flows through conduit 30, valve 26 and conduit 28 to the tank.

The cylinder 36, accordingly, moves upwardly.

Some distance before it reaches the upper limit of its travel cam I26 opens limit switch I24 and thusbreaks the holding circuit of the relay I20, the initiating circuit for this relay being opened at the limit switch I I4, which opened as the cylinder 64 started upwardly. The opening of relay I20 deenergizes the solenoid of valve 84, permitting the latter to move to the left under its spring bias thus reversing connections to cylinder 16 and causing the latter to return to the right,

unclamping the work piece 12, which is clamped beneath the abutment 14, and retracting the holder 15 from beneath the work piece.. During this interval, it will be noted that both cylinders 16 and 36 are jointly connected to both pumps I6 and I8. The pressure on cylinder" is limited, however, by valve 46.

- As the cylinder 16 starts to the right, cam I3 4 releases limit switch I30, opening the initiating circuit for relay I38 and for relay I54. As cylinder 16 completes its rightward movement, cam I13 closes relay I12. and closes one break in the initiating circuit for relay I18. Whencylinder 36 completes its upward movement, the tool 68 is pulled clear through the work piece 12, which drops by gravity and is pushed to one side by the limit switch I56, conductor I80, permitting valve 26 to spring center, thus by-passing the delivery or pump I6 and stopping movement of cylinder 36, and permitting valve 82 to move to the left under its spring bias, thus breaking the circuit connecting pumps I6 and I8. The relay I18 closes the circuit through conductor I82 to the solenoid I88. The stem I10 of valve 26 is, accordingly, moved downwardly. The shifting of valve 26 downwardly connects the rod end of cylinder 36' to the delivery side 01 pump I6, through conduits 28 and 38, thus causing the cylinder to descend.

As the cylinder 36 reaches the bottom of the stroke, cam I43 opens the limit switch I42, breaking the holding circuit I40 for relay I38 and also the holding circuit I88 ior relay I18. The initiating circuit for relay I38 is open at limit switch I30 while the initiating circuit for relay I18 is open at limit switch I56. Opening of the relay- ,these cycles so long as the holding circuit III of relay" I08 is not opened at the stop switch I I2. 'When this switch is depressed, relay I08 opens the initiating circuits I l6-I I8 for relay I26. Thus, no matter at what phase of the cycle the button H2 is depressed, the machine will continue to operate until the end of that cycle and then stop due to inability of the limit switch II4 to energize the relay I20.

While the form of embodiment of the invention a as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the'scope of the claims which follow.

What is claimed is as follows:

1. In a hydraulic power transmission system the combination of means forming a source of fluid under pressure, a main motor operable by fluid delivered from said source, a first and second auxiliary motor also operable by fluid delivered from said source, valve means for controlling the supply of fluid to the motors, a' .control circuit for operating the valve means and means in the circuit operated by movement of the motors for causing operation or the motors in a predetermined sequence of forward movements or the motors and a difierent sequence of reverse movements thereof, starting means in the circuit cfl'ective when operated to cause repeated cycles of operation of the motors in sequence under the control of the motor operated means, and stopping means in the circuit eflective when operated to condition the circuit for stoppage of the motors when they reach a predetermined position in the cycle of sequential movements.

2. In a hydraulic power transmission system the combination of a plurality of 'pump means forming a source of fluid under pressure, a main motor operable by fluid delivered from said} iary motortoanother pump and a valveior conv necting the main motor to both pumps during movement in one direction.

3. In a hydraulic power trn system the combination of a plurality of pump means forming a source offluid under pressure, a main motor operable by fluid delivered from said source, an auxiliary motor also operable by fluid delivered from said source, valve means for controlling the supp y of fluid to the motors, a control circuit for operating the valve means and means in the circuit operated by movement of the motors for causing operation of the motors in a predetermined sequence of forward and retors, means forming a selectively operable connection from bothv pumps to the main motor, motor operated means for controlling said valves to energize the auxiliary motor forwardly and then the main motor forwardly, and means for imparting a reverse movement to the auxiliary motor to release the work piece before completion of the forward movement of the main motor.

5. In a hydraulic power transmission system for operating a machine tool having a main slide for operating on a piece' of work and an auxiliary slide for moving and holding a work piece into position for such operation,-the comverse movements, means connecting the main nbination of a main motor connected to operate motor to one pump, means connecting the auxiliary motor to another pump and a valve for connecting the main motor to both pumps during movement in one direction, said control circuit having connections for operating the last said valve.

4. In a hydraulic power transmission system for operating a machine tool having a main slide for operating on a piece of work and an auxiliary slide for moving and holding a work piece into position for such operation, the combination of a main motor connected to operate the main slide, an auxiliary motor connected to operate the auxiliary slide, individual pumps for operating the motors, a circuit, including valve means for controlling the motors individually, connecting the pumps with their respective methe main slide, an auxiliary motor connected to 

